Means for obvlating the action of heat in a projector upon the backing of the imagesto be projected



Dec. 13, 1927. 1 1,652,817 M. COUADE MEANS FOR OBVIATING THE ACTION OF HEAT m A PROJECTOR UPON THE BACKING OF THE IMAGES. TO BE PROJECTED Filed Nov. 3, 1925 Maurice Couadg- INVENT RJ A fi W Patented Dec. 13, 1927.

UNITED STATES 1,652,817 PATENT OFFICE.

MAURICE COITADE, OF PARIS, FRANCE, ASSIGNOR TO PATHE CINEMA, ANCIENB ETABLISSEMENTS PATHE ERERES,

OF PARIS, FRANCE.

MEANS FOR OBVIATING THE ACTION OF HEAT IN A PROJECTOR UPON THE BACKING OF THE IMAGES TO BE PROJECTED.

Application filed November 8, 1825, Serial No. 66,468, and in France November 15, 1924.

In known practice, the heatin action of the projecting beam upon the ackin or support of the images to be projected, is obviated by delivering currents of air upon one or both sides of said backin but in this event only a part of the air WllCll is thus sup lied can be utilized for the cooling of said backing, since the air expands 1n the atmosphere when discharged from the supply conduits.

In certain devices, a stream of air is circulated between said backing and a lass plate disposed on the side next the con enscr, and herein the air under pressure will I blow the backing intov a curved sha e if it is flexible as in cinematographic has, this effect depending upon the force of the stream.

- lt has further been pro osed to place between the condenser and said backing a glass plate consisting of a material absorbing the heat rays. but such lates. only absorb a ortion of the heat ant cut ofi' a great part o'the light. j The present invention has for its object a device whereby we obviate the action of the heat from a beam of light from a projector upon the backin of the images to be projected, by means of a surface cooling of said backing by a current of air. Said device consists essentially in the fact that it comprises a narrow sheath in the middle part of which is disposed the backing of the iruage-lihu or plate--the front and rear walls of said sheath consistin g of a transparent substance such as glass, mica, or the like; thesheath is traversed by a current of air which passes upon the two faces of said backing. Since the pressure and the air cir- 4o culation are the same on both sides of the backing, the latter will remain in a flat position and will also be cooled. The said device permits of eliminating the use of heat absorbing glass, and in this manner the entire output of the illuminant is maintained.

The transparent walls may consist either of glass plates with parallel faces or of plano-conrex lens elements whose convergent cll'cct will be combined at the rear part with that of the condenser and in front with that of the objective.

The appended drawing example two embodiments of said invention. Fig i 1 is a section of a first embodiment shows by way of per endicular to the direction of the film.

ig. 2 is a similar section of a secondembodiment.

In Fig; 1, 1 is the backing for the image or images to be projected; 2 is the frame of the device; 3 and a are two transparent walls disposed on either side of the backing l. The air which is supplied under pressure through the conduit 5 will pass over both faces of the backing -1 and will then'esca e into the atmosphere in the direction of the arrow 7. I

The devices shown in Fig. 2 is a modification of Fig, 1, and like reference numerals indicate corresponding parts' The modification consists 1n the form of the transparent walls which herein consist of planeconvex lenses 6 and 7 with the facing the interior of the sheatl Obviously, the invention is not limited to the construction shown in the drawing, and in particular the current of air, instead of bein supplied transvcrsally with reference to tie backing, ma be supplied in a vertical or oblique ircction, provided the pressure is the same on both sides of the acking.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a projection apparatus the combination of a front and a rear transparent wall respectively disposed on either side of the support for the images to be projected and whereby a narrow sheath for said support is provided, with means for causing a current of air to flow throughout said sheath and over both faces of said support alwa s in the same direction from one edge to th s other edge of said support.

2. In a projection apparatus the combination of a front and a rear transparent wall respectively disposed on either side of the support for the images to be projected and whereby a narrow sheath for said support is provided, an air inlet conduit opening laterally into said sheath in front of the edge of said support and means for circulating air through said conduit and sheath, alwa s in the same direction from one edge to tie other edge of said support.

3. In a projection apparatus the combination of front and rear glass'platcs with parallel faces respectively disposed on either plane part side of the support for the images to be of the support for the images to be projected projected and whereby a narrow sheath for and whereby a narrow sheath for said supsaid support is provided with means for port is provided with means for causing causing a current of air to flow throughout a current of air to flow throughout said 5 said sheath and over both faces of said supsheath and over both faces of said support 15 port always in the same direction from one always in the same direction. from one edge edge to the other edge of said support. to the other edge of said support.

4. In projection apparatus the combina- In testimony whereof I have signed my tion of front and rear plano-convex lens name to this specification.

10 elements respectively disposed on either side MAURICE COUADE. 

